In electrical power applications, particularly those relating to aerospace and military, there is a need for a heavy-duty electrical connector having a combination of qualities which are not provided by known existing connectors. For example, a fully satisfactory connector of this kind would possess high resistance to electromagnetic interference, quick mating and unmating of parts, means for sealing the cable against the ingress of moisture, dirt, dust, or the like and audible/tactile/visual mating and unmating indication means.
Moreover, many techniques commonly utilized in relatively small-size electronic releasable connectors are not suitable for larger and heavier electrical power connectors. A heavy duty connector will, of necessity, terminate at a large cable which because of its relatively large conductors (e.g., 16 gauge to 4/0 gauge) and external shielding or metal sheath, is extremely rigid as compared to, say, a cable containing 22 gauge to 20 gauge conductors.
In U.S. Pat. No. 4,066,315 there is described an electrical cable connector with keyed parts which are lockingly intermated by rotation of a coupling housing, the latter including a separate internal nut that drives the connector parts. This connector is widely accepted at this time as an excellent means for releasably interconnecting electronic equipment. Frequently the relative orientation of the keys and keyways is not precise making it necessary to rotate or twist the cable to align the connector parts. In using this type of connector on a heavy duty application, the torgue required to twist a cable of large conductors and connector part secured thereto, can result in misalignment of the coupling housing and internal nut which would prevent mating of the connector parts.
The patented electrical connector compensates for accumulated tolerances of its different components by incorporation of various spring-type devices between the coupling housing and the other parts. However, these devices are sensitive to and adversely affected by forces applied to the cable tending to pull the connector apart. That is, cable loads sufficient to deflect the spring devices will effect separation of the connector parts at the interface producing undesirable contact movement and reduction or even total loss of compression at the interface seal.
Still further, a fully satisfactory electrical connector of this category must be able to withstand a variety of hostile environments, such as seismic and pyrotechnic shock, humidity, temperature extremes, icing, sand and dust.